The risk for colorectal cancer (CRC) in young adults appears to be lower than what has been previously estimated, as previous studies did not differentiate between colorectal adenocarcinoma and carcinoid tumors, which are incidental findings, suggest experts.

New estimates for the risk of CRC in young adults, which differentiate colorectal adenocarcinoma from other types, appear in a study published in the Annals of Internal Medicine. The new analysis revealed that 4% to 20% of the lesions previously described as CRC were not adenocarcinoma but carcinoid tumors.

Investigators determined the incidence rates of early colorectal cancer, using SEER data from 2000 to 2016, and stratified the data by histologic subtype (primarily adenocarcinoma and carcinoid tumors), age group (20-29, 30-39, 40-49, and 50-54 years), and subsite. The absolute incidence rate in the age groups of 20-29 and 30-39 years was very low compared to 40-49 and 50-54 years age groups. The greatest changes in adenocarcinoma 3-year average annual incident rates (2000 to 2002 vs 2014 to 2016) were for rectal-only cases in those aged 20-29 years (+39%), as well as rectal-only cases in the 30-39 years (+39%), and colon-only cases in the age group of 30-39 years (+20%)… (Medscape)